CERC ISTS Waiver Relief: Delayed Solar Projects 2026

Quick Answer

What CERC's Fifth Amendment Actually Changes

India began phasing out ISTS (Inter-State Transmission System) charge waivers for new solar, wind, and hybrid projects from July 2025. That phase-out left a real gap: projects that signed contracts and started construction expecting a waiver, then got stuck behind a transmission line that wasn't ready on schedule, a problem entirely outside the developer's control. CERC's draft Fifth Amendment to the Sharing of Inter-State Transmission Charges and Losses Regulations, 2026, published July 31, 2026, is built to address that gap. It is not a return to the old blanket waiver. It is targeted relief for projects delayed by transmission unavailability, plus a separate, unrelated win for battery storage.

What CERC's Fifth Amendment Actually Changes

Projects meeting all three stay eligible for an ISTS charge waiver even if the transmission network itself is the reason commissioning slipped.

The Waiver Is Graded, Not Flat

This is not a blanket 100% waiver regardless of delay. CERC's proposal sets a graded scale, 100% down to 25%, tied to the project's originally scheduled commencement date. The exact breakpoints, which specific delay windows land at which percentage, aren't detailed in current trade coverage of the draft, and the primary draft text wasn't directly accessible at the time of writing. Confirm the graduated schedule against the final CERC notification before quoting a specific waiver percentage to a client.

BESS Gets a Separate, Bigger Win

Independent of the delay-relief provisions, the draft extends the ISTS charge waiver period for battery storage integrated with a Renewable Energy Generating Station (REGS) or Renewable Hybrid Generating Station (RHGS) from 12 years to 25 years from the storage system's commercial operation date. This applies when the renewable plant and the battery are scheduled as a single integrated generating station, not as separate assets. For any C&I EPC pairing storage with a ground-mount project, this materially changes the 25-year financial model, aligning the storage waiver window with the typical PPA duration for the first time.

Other Provisions in the Draft

Why This Matters for EPCs

Transmission delay is not a rare edge case. It is one of the most common reasons a utility-scale or large open-access project misses its scheduled commissioning date, and until this draft, that delay carried real financial risk on top of the schedule risk, losing the ISTS waiver on a project the developer did nothing wrong to delay. For EPCs advising developer clients or structuring their own IPP pipeline, this draft is the difference between a stalled project quietly losing millions in transmission charges over its operating life, and that risk being explicitly protected against, provided the paperwork is filed correctly and on time.

Common Mistakes EPCs Should Avoid

• Treating this as settled law. It is a draft. Public comments close August 31, 2026, and the final regulation may differ from what's proposed.
• Missing the documentation deadline. Eligible projects must submit their contracts to CTUIL and NLDC by January 31, 2027, a hard administrative cutoff separate from the commissioning timeline itself.
• Confusing this with the existing wind and solar ISTS waiver deadline of June 30, 2028. That's a different, already-in-force mechanism. This draft is specifically about relief for projects delayed past their original schedule.
• Assuming any delay qualifies. The three-part eligibility test, connectivity date, contract tenure, and the two-month GNA commissioning window, all have to be met, not just one.

How This Fits Into a Reslink Workflow

A project's eligibility for ISTS relief, and the BESS waiver extension, changes the 25-year financial model an EPC presents to a client or lender. Reslink's proposal software builds that 25-year projection from the same design workflow used for system sizing and BOM, so when this draft becomes final, updating the transmission-charge assumption in one place updates every proposal generated from it, rather than requiring a manual recalculation project by project.

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Frequently Asked Questions

Q1. What is CERC's Fifth Amendment to the ISTS Sharing Regulations?

It's a draft amendment, published July 31, 2026, to the Central Electricity Regulatory Commission's regulations governing how inter-state transmission charges are shared. The most relevant provisions for solar and wind EPCs are relief for projects delayed by transmission unavailability, and an extended ISTS waiver period for battery storage integrated with a renewable plant.

Q2. Is this rule already in effect?

No. It's a draft. CERC has invited public comments and suggestions through August 31, 2026. The final regulation, once notified, may differ from the current draft.

Q3. What projects qualify for the delay relief?

Projects need a firm connectivity start date between July 1, 2025, and June 30, 2028, a signed power purchase or supply agreement of at least seven years by December 31, 2026, and commercial operation within two months of General Network Access becoming effective.

Q4. How much does the BESS ISTS waiver change under this draft?

The waiver period for battery storage integrated with a renewable generating station extends from 12 years to 25 years from the storage system's commercial operation date, provided the storage and the renewable plant are scheduled as a single integrated station.

Q5. What's the documentation deadline for eligible projects?

Developers must submit copies of the relevant contracts to CTUIL and the NLDC by January 31, 2027, separate from the project's own commissioning timeline.

Q6. Does this replace the existing June 2028 ISTS waiver deadline for wind and solar?

No. That deadline, tied to commissioning before June 30, 2028, is a separate, already-in-force mechanism. This draft specifically addresses projects that miss their schedule because the transmission network wasn't ready.

Sources

• Central Electricity Regulatory Commission, Draft Regulation index (cercind.gov.in/Draft_reg.html): confirms the draft's existence, exact title, and the August 31, 2026 public comment deadline. Fetched directly.
• SolarQuarter, August 3, 2026: reports the three-part eligibility test, the graded 100% to 25% waiver, and the January 31, 2027 CTUIL/NLDC documentation deadline.
• EQ Magazine (eqmagpro.com): reports the BESS waiver extension from 12 to 25 years and the single-integrated-station condition.
• Energetica India, August 1, 2026: reports the REIA definition and the GDAM 51% renewable-requirement provision.
• Power Peak Digest, August 3, 2026: reports the hydro PSP contract-level compliance approach and confirms the draft's July 31, 2026 publication date.
• Business Standard / Reuters, August 3, 2026: confirms India's July 2025 ISTS waiver phase-out for new solar, wind, and hybrid projects, the policy context this draft partially addresses.